What exactly does posi mean, is il like limited slip or am i completely wrong?

 

Posi is a generic Slang term we use for Limited Slip Differentials. There are different kinds with Limited Slip being the most popular. Limited slip uses clutches and does what the name implies. It only allows limited slippage of the tire with the least traction???? making it many times better than an open differential. It's popular because it's road worthy and you have no idea it's there until you look at the black marks you just left.

Then there are lockers that actually mechanically lock the two axles together when one tire is spinning considerably faster than the other. Most lockers are noisy and the stock GM units almost always get destroyed with high HP and TQ applications. They also don't like to take turns sometimes, locking, unlocking and clanking when turning. The whole reason many cars have an open differential is because of the difference in tire speeds when turning. Not good for power transfer but when you're going to pick up Timmy from school, having both tires spinning doesn't mean much. Hope this answers your question and I am not ENTIRELY sure on the exact limited slip whether it's the tire with the least or most traction.